Animal studies in mice, pigs and cats suggest it is “feasible” coronavirus infections can arise via the womb if the mother is carrying the pathogen, the Midwestern scientists wrote in the Journal of Clinical Virology.

Infection after birth appears to be more of a “clear risk”.

With “limited” research available on the circulating coronavirus, the scientists looked at other strains of the same class.

Although it was associated with pregnancy complications, Sars was not found to transmit from an infected mother to her unborn baby.

Speaking of coronaviruses as a class, Professor Andrew Shennan from King’s College London said: “Transmission from mother to baby has not previously been observed.

“Studies have shown coronavirus has not passed to amniotic fluid, foetal cord blood, placentas or the genital tract of infected mothers”.

The circulating coronavirus is more genetically similar to Sars than any other strain of that class.

So much so the International Committee on Taxonomy of Viruses “determined it is the same species as Sars but a different strain of the species”, Dr Nathalie MacDermott from King’s College London previously said.

The Midwestern scientists added: “To date, the morbidity and mortality described for [Sars] infections during pregnancy do not appear to be as severe for [the new coronavirus].

“Most reviews have concluded there is no conclusive evidence of transplacental transfer of [the new coronavirus] from mothers with [the infection].”

The scientists pointed to a recent study that looked at 38 pregnant women who tested positive for the coronavirus.

The study found “no evidence” of infection among the newborns and “no confirmed case” of virus transmission in the womb.

A later paper of 55 pregnant women who tested positive for the pathogen similarly found “no definite evidence” they passed the infection to their babies intrauterine.

Three of the women gave birth to babies who “presented with early onset infection” around two days later.

“Given that all the infected babies were first shown to be positive at two days, I suspect they were infected after being brought into the world rather than in the womb”, Professor Paul Hunter from the University of East Anglia previously said.

“This does not change the current consensus that transmission in the womb is unlikely”.

Tests of the women’s amniotic fluid, umbilical-cord blood and breast milk all came back clear.

“It seems more likely the three infants were infected very soon after delivery, possibly from the mother’s fingers”, Professor Andrew Whitelaw from the University of Bristol previously said.

Infected newborns may have caught the virus via “aerosol and droplet transmission in the delivery room, or transmission in the birth canal”, wrote the Midwestern scientists.

A pregnant swimmer visits Bondi beach in Sydney after it is reopened. (Getty Images)

Coronavirus: What is the advice for pregnant women?

Pregnant women have been urged to be particularly careful not to catch the coronavirus, however, this may be a case of being on the safe side.

“Infections and pregnancy are not a good combination in general and that is why we have taken the very precautionary measure while we try and find out more,” Professor Chris Whitty, the UK’s chief medical adviser, previously said.

Nonetheless, pregnant women did not make up the 1.5 million vulnerable Britons who have been told to stay in their home for three months. These include severe asthmatics and blood-cancer patients.